Anatomic brace fracture for the knee

Abstract

An anatomic fracture brace mechanism for knee braces to provide lateral restraint and delimited supportive motion of the knee joint permitting weight bearing ambulation of the patient during healing of leg fractures or other traumas, a fracture brace being constructed with a brace mechanism utilizing an asymmetrical four-bar, cross-linkage to follow, as closely as mechanically practical, the polycentric motion of the human knee.

What is claimed is: .[.1. A brace mechanism having a four-bar linkage for use in a paired arrangement on each side of a user's leg in an anatomic knee brace comprising: 
     
        user's knee..]. .[.5.  The brace mechanism of claim 4, wherein said fourth link comprises a flat plate and said locating means comprises a hole in said plate..]. .[.6. The brace mechanism of claim 1 having adjustable stop means for selectively limiting articulation of said extension portion of said first upper extension link relative to said extension portion of said second lower extension link in said brace mechanism..]. .[.7. The brace mechanism of claim 6 wherein said stop means comprises first and second moveable stops on said fourth link arranged on each side of said second link..]. .[.8. The brace mechanism of claim 1 comprising further locking means for locking said brace mechanism with said brace mechanism with said vertical extensions vertically aligned..]. .[.9. The brace mechanism of claim 8 wherein said third connecting link includes a tab extension which aligns with said extension portion of said first extension link on vertical alignment of said two extension links, said locking means comprising a slide collar slidable on said extension portion of said first extension link and engageable around said tab extension to lock said tab extension to said first extension link thereby locking said brace mechanism..]. .[.10. The brace mechanism of claim 3 having further stop means for limiting the articulation of said brace mechanism in one direction to vertical alignment of said two extension members..]. 
     
     
        .Iadd.     A brace mechanism having a four-bar linkage for use in a paired arrangement on each side of a user's leg in an anatomic knee brace comprising: a. a first extension link with an upward extension portion adapted and constructed to align with a user's leg above the knee, and with a lower end portion, having first and second spaced pivots;   b. a second extension link with a downward extension portion adapted and constructed to align with a user's leg below the knee, and with an upper end portion having spaced third and fourth pivots, said distance between said third and fourth pivots being greater than said first and second pivots;   c. a third connecting link having a first end connected to said first pivot on said first link and a second end connected to said fourth pivot on said second link;   d. a fourth connecting link having a first end connected to said second pivot on said first link and a second end connected to said third pivot on said link wherein upon alignment of said extension portions, said first pivot is located on said end portion of said first link proximate said extension portion and said second pivot is spaced from said first pivot in a downward angled direction, said third pivot is located on said end portion of said second link proximate said extension portion and said fourth pivot is spaced from said third pivot in an upward angled direction toward said second pivot; and said fourth link crosses said third link;   e. a locating means for aligning the brace mechanism in a paired arrangement on each side of a user's leg, the locating means being positioned at the bone prominence of a user's femur at the side of a user's knee when the brace mechanism is installed on a user; and   f. a locking means for locking said brace mechanism with said extension links aligned, wherein said third connecting link includes a tab extension which aligns with said extension portion of said first extension link on alignment of said two extension links, said locking means comprising a slide collar slidable on said extension portion of said first extension link and engageable around said tab extension to lock said tab extension to said first extension link thereby locking said brace mechanism; whereby said four-bar linkage is constructed and arranged to generate a polycentric motion with dual centrodes progressing from a common centrode point when said extension portions are aligned against a user's straight leg and diverging with asymmetric trajectories when said extension portions are angled conforming to a user's bent leg, the asymmetric trajectories of a four-bar linkage approximating the asymmetric trajectories of the polycentric motion of a user's knee. .Iaddend. .Iadd.12. A brace mechanism having a four-bar linkage for use in a paired arrangement on each side of a user's leg in an anatomic knee brace comprising:   a. a first extension link with an upward extension portion adapted and constructed to align with a user's leg above the knee, and with a lower end portion, having first and second spaced pivots;   b. a second extension link with a downward extension portion adapted and constructed to align with a user's leg below the knee and with an upper end portion having spaced third and fourth pivots, said distance between said third and fourth pivots being greater than said first and second pivots;   c. a third connecting link having a first end connected to said first pivot on said first link and a second end connected to said fourth pivot on said second link;   d. a fourth connecting link having a first end connected to said second pivot on said first link and a second end connected to said third pivot on said second link wherein upon alignment of said extension portions, said first pivot is located on said end portion of said first link proximate said extension portion and said second pivot is spaced from said first pivot in a downward angled direction, said third pivot is located on said end portion of said second link proximate said extension portion and said fourth pivot is spaced from said third pivot in an upward angled direction toward said second pivot, and said fourth link crosses said third link and,   e. a locating means on the four bar linkage for aligning the brace mechanism in a paired arrangement on each side of a user's leg in a position which maximizes conformity of the motion of the brace mechanism with the motion of the user's leg, the locating means on one brace mechanism being positionable at the bone prominence of a user's femur at the side of a user's knee when the brace mechanism is installed on a user; wherein said four-bar linkage is constructed and arranged to generate a polycentric motion with dual centrodes progressing from a common centrode point when said extension portions are aligned against a user's straight leg and diverging with asymmetric trajectories when said extension portions are angled conforming to a user's bent leg, the asymmetric trajectories of the four-bar linkage approximating the asymmetric trajectories of the polycentric motion of a user's knee when the locating means is properly positioned at the femur bone prominence and the brace mechanism is properly aligned on each side of the user's leg in said paired arrangement..Iaddend. .Iadd.13. The brace mechanism of claim 12 wherein said third and fourth links have an effective length between   
     
     
        pivots which is approximately equal. .Iaddend. .Iadd.14.  The brace mechanism of claim 12 wherein said extension portions on each of said first and second links have a longitudinal axis and each of said pairs of pivots on said end portions define an axis having an orientation approximately 45° from said longitudinal axis of said extension portions. .Iaddend. .Iadd.15. The brace mechanism of claim 12 wherein said fourth link comprises a flat plate and said locating means comprises a hole in said plate. .Iaddend. .Iadd.16. The brace mechanism of claim 12 having adjustable stop means for selectively limiting articulation of said extension portion of said first upper extension link relative to said extension portion of said second lower extension link in said brace mechanism. .Iaddend. .Iadd.17. The brace mechanism of claim 16 wherein said stop means comprises first and second moveable stops on said fourth link arranged on each side of said second link. .Iaddend. .Iadd.18. The brace mechanism of claim 12 comprising further, locking means for locking said brace mechanism with said extension links aligned. .Iaddend. .Iadd.19. The brace mechanism of claim 18 wherein said third connecting link includes a tab extension which aligns with said extension portion of said first extension link on alignment of said two extension links, said locking means comprising a slide collar slidable on said extension portion of said first extension link and engageable around said tab extension to lock said tab extension to said first extension link thereby locking said brace mechanism. .Iaddend. .Iadd.20. The brace mechanism of claim 14 having further, stop means for limiting the articulation of said brace mechanism in one direction for alignment of said two extension members. .Iaddend.